As known in the art there exist standards relating to the size and structures of containers. ISO standard 668: 1988/1:1993 specifies the location of the corner fitting apertures of the container with respect to one another, and the dimensions of the containers. ISO standard 1161 specifies the shape of the corner fitting apertures of the container, and the permissible mode of handling the container is specified in the standard SFS-ISO 3874.
As known in the art, empty containers generally weigh below 5000 kg. The standardized container lengths are 10, 20, 30 and 40 feet. The 40 foot long containers have a height of either 8½ feet or 9½ feet and the 20 foot long containers have a height of 8½ feet. The prior-art container moving devices, for example, straddle carriers, usually comprise length adjustment, so that the handling length can generally be adjusted to be 20, 30 or 40 feet. Applications are also known in which the handling length can be adjusted to be 35 feet. Containers are handled as empty and as full.
With respect to the prior art, reference may be made, for example, to U.S. Pat. Nos. 3,863,970, 5,280,980 and 6,145,903. In these prior-art arrangements, which mainly relate to the handling of full 20 foot containers, two containers are placed longitudinally one after the other in the handling equipment. Such devices are generally massive because full containers weigh as much as 40 tonnes. In addition, handling is problematic because the structure with its containers becomes rather long, and therefore they also have not been suitable for the handling of longer 40 foot containers.
As known in the art, empty containers are stored in ports such that several containers are placed one upon the other. Containers are handled by means of transfer and transport devices, for example, straddle carriers, the gripping member of which grips the container from above one container at a time, so that the container can be transferred to a desired location.